Sys.Application.add_init(AppInit);

function AppInit(sender) {
    // initiate begin and end request handlers
    if (Sys.WebForms != undefined) {
        Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(BeginRequestHandler);
        Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
    }
};

function BeginRequestHandler(sender, args) {
   
}

function EndRequestHandler(sender, args) {
    try {
        AsyncDone();
    }
    catch (e) { }
}